The present invention relates generally to medical products and compositions for making same. More specifically, the present invention relates to non-PVC materials and medical containers, devices, and tubing made therefrom.
Typically, medical tubing, for example for use in blood collection sets as the donor tubing, is constructed from plasticized polyvinyl chloride (PVC). Usually, the PVC is plasticized with DEHP. Likewise, some medical containers and devices are constructed from plasticized polyvinyl chloride.
In one method of constructing such containers, the container is filled through an open-ended filling port. A membrane tube closure is then coated with a solvent such as cyclohexanone and inserted into the fill port tube. During this process, a chemical bond is achieved between the fill port and membrane tube closure.
Recently there has been concern with respect to the use of DEHP plasticized PVC. DEHP has been alleged to be a suspected carcinogen. However, the characteristics that are afforded by plasticized PVC are very desirable especially in the medical area and for uses such as, for example, the donor tube in blood collection systems.
With respect to tubing, for example, it typically must have low temperature characteristics. Furthermore, it is desirable that the tubing can be solvent bonded to a PVC material: the containers to which the tubing is secured are usually constructed from PVC. It is also desirable that the tubing is RF sealable so as to be compatible with blood tubing sealing equipment presently used.
Likewise, medical containers must exhibit certain desirable properties. It is desirable that the container can be sealed, either to itself or other components such as tubing, by conventional sealing methods such as radio frequency, sonic welding, thermal welding, and medical grade solvent bonding systems. The containers must be thermally stable at 121.degree. C. without irradiating or cross-linking for autoclavability. The scrap should be recyclable. The container should withstand low temperatures (-60.degree. C. to -80.degree. C.) and should be compatible with multilayer structures that may not require a tie layer. The container needs to be sufficiently permeable to WVTR to minimize haze during autoclaving. For use as a blood bag, the container must be sufficiently permeable to oxygen and carbon dioxide to store blood components such as platelets and plasma. Additionally, the container should be scuff resistant.
Presently, plasticized (flexible) polyvinyl chloride (PVC) materials are widely used for medical applications, such as medical solution containers (parenteral), storing red cells, plasma, and platelet containers. The desirable properties of the above applications include: extrudability; moldability; flexibility; transparency; resistance to heat; cost; and ability to be sealed using conventional sealing technology, such as radio frequency, heat sealing, sonic welding, thermal sealing, and medical grade solvent system.
Typically, the containers constructed from plasticized PVC are sterilized by autoclaving at 121.degree. C. for 60 minutes or less. Therefore, any material that will be used as a substitute for plasticized PVC must withstand such autoclaving (121.degree. C., 60 minutes).
Polyolefinic containers made from ethylenevinyl acetate have been developed for medical solutions. Containers made from ethylenevinyl acetate (EVA) are not thermally stable at 121.degree. C. Therefore, the film or container needs to be radiated by electron beam process or gamma radiation to achieve autoclavability.
Although there are other components in the art from which, arguably, such medical products could be created, each of these components suffers certain disadvantages. Most importantly, the resultant product does not have the same desirable characteristics as a plasticized PVC product.
For example, flexible polyester is not as RF responsive as is plasticized PVC. Aliphatic polyurethane is not autoclavable. Further, with respect to tubings, tubings created from such materials due to their characteristics cannot be used on currently used commercial machinery in, for example, a blood collection system.
U.S. patent application Ser. No. 07/270,006, filed Nov. 14, 1988, discloses a citrate ester in a non-PVC material. U.S. patent application Ser. No. 07/494,045, filed May 15, 1990, is a divisional application to that patent application. Both of these applications are assigned to the assignee of the present invention.